package luogu;

import java.util.Scanner;

public class P1914 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String s = sc.next();
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) + n > 'z'){
                System.out.print((char) (s.charAt(i) - 26 + n));
                continue;
            }
            System.out.print((char) (s.charAt(i) + n));
        }
    }
}
